your bedroom is on the second floor of your house, you have a big window on the side of the wall facing directly across the window of the neighbouring house, although that was never much of a problem, since that house has been on sale for forever, until a few weeks ago

A family had just bought the neighbouring house a few weeks ago, you didn't know much about them, just that it was 2 nice looking middle aged couple with a teenage son around your age, and his bedroom was the one with the window opposite you, so you both had a clear view of eachother, without the curtains of course.

It was a fuss for a few weeks, there were a lot of vans moving in and out the area before they officially settled in

(Start your scenario however you want, for example: he has friends over, he goes over to your place to ask for something, etc)